Implantable cardioverter defibrillators (ICDs), pacemakers and other cardiac pacing devices are typically implanted in a patient transvenously. The sensing and pacing electrodes are implanted in the heart, attached to distal ends of associated leads. The leads and electrodes are typically implanted using an introducer sheath or catheter. The leads are preferably isodiametric so that they can be easily implanted using a standard introducer sheath. Once the physician has determined that the electrodes are correctly placed, and in order to test the pacing device, the leads must be connected at their proximal ends to the control system, the ICD or pacemaker, to test the overall system. This testing involves removing the sheath and positioning the device in a device pocket typically located in a pectoral region of the patient. The removal of the introducer sheath typically involves slitting of the sheath and peeling the sheath from the lead. Removing the sheath and positioning the device in the patient may at times dislodge the lead from its ideal location.
Typically, the control system includes one or more header ports into which the leads are connected. The headers each include a lumen, which has a standard inner diameter that is usually larger than the lead to be connected. In order to make a good connection with the header, the diameter of the lead must be increased. This is typically achieved using a lead having a connector permanently attached to the proximal end of the lead. Alternatively, with an isodiametric lead, an upsizing sleeve may be attached at the time of implantation of the device, using medical adhesive to secure the sleeve to the lead. The sleeve or connector is pushed into the header of the control system. Once a sleeve is attached to an isodiametric lead using adhesive, it cannot be removed therefrom.
Thus, if testing of the pacing device indicates that the electrodes must be repositioned, the introducer sheath cannot be replaced over the lead because the lead is not isodiametric due to the additional diameter of the connector or sleeve. The electrode and lead must then typically be completely removed from the patient, and a new sheath must be loaded with the lead must be inserted within the patient. Not only does this require a physician to ensure that a number of sheaths are available during the procedure in case new sheaths need to be used, but also adds to the time taken for the implantation of the pacing device, especially when the pacing location is difficult to access, which increases the time required for the implant procedure. In addition, the introduction of the medical adhesive may also add to the risk of contamination of the sterile field/environment.